This invention is directed to method of forming an endoscopic instrument body from metal, in particular, a method for forming an endoscopic instrument body by rolling the metal.
Endoscopic instruments generally have an outer sheet and an endoscopic instrument body contained within the sheet and a bundle within the endoscopic instrument body. The bundle may comprise anything from cables for controlling a tool at a distal end of the endoscopic instrument body to light fibers and electrical wires for supporting a light and camera at the end of the endoscopic instrument body. The tube supports the bundle as it is inserted into a patient. The endoscopic instrument bodies are formed of metal to provide support and protection to the bundle as it is used during an operation. To that end the endoscopic instrument bodies are formed of metal such as stainless steel because of their strength and rigidity across a distance.
In order to support the bundles within the endoscopic instrument body, to make them functional, the sides of the endoscopic instrument body are often cut, provided with openings, slits, or other features (collectively referred to as features) so that the bundle within the endoscopic instrument can interact with other parts of the endoscope not within the endoscopic instrument body. The jobs to be performed by the endoscopic instrument will determine the bundle and the type of bundle will determine the types of features placed on the endoscopic instrument body.
It is known from the prior art to form seamless tubes, a plug of metal is drawn to a predetermined length substantially corresponding to the length of the desired endoscopic instrument body. The inner diameter and outer diameter of the endoscopic instrument body are determined by the length of the draw. Because a predetermined amount of material is used as a starting material, the longer the tube is drawn, the thinner the endoscopic instrument body walls become changing the dimensions of the outer diameter and inner diameter. Once the endoscopic instrument body has been drawn, it is then hand finished and cut to provide the necessary features. The forming of the features within the endoscopic instrument body is usually done by hand and therefore is time consuming.
It is also known to form an, endoscopic instrument body by rolling a flat stock of metal into a tube. The tube is usually extremely long, having a length, by way of example, of 500 feet or more. The flat stock is rolled along the grain so that the tube can support a finished product having a length of 500 feet or more. The tube is rolled into a circle. Therefore the dimensions of the narrow rolled stock are the outside diameter of the roll by over 500 feet in length. The seam is then welded. A plug is inserted at one end of the tube and the tube is drawn to reduce the outer diameter of the tube until it reaches the desired outer diameter of the final endoscopic instrument body product. The 500 foot long tube is then cut to the desired endoscopic instrument body length. Once it has been cut, the features are then again added by hand.
These prior art methods have been satisfactory. However, they suffer from the disadvantage that first, because a drawing step is required in both methods of manufacture, it is difficult to produce a predetermined outer diameter and inner diameter with accuracy. Furthermore, because each process requires that the features be added after formation of the endoscopic instrument body, the features must be added by hand tooling which results in less precision, less accuracy and is time consuming.
Accordingly, a method for forming an endoscopic instrument body which overcomes the prior art shortcomings by providing a method which forms an endoscopic instrument body with greater accuracy and more efficiency is desired.